"Common rings" serve exactly the purpose they were added for even in the past BG games: they are so called "vendor trash".
Stuff you carry around only to dump it on the first vendor you meet for money.
And so is a lot of other stuff in the game.
I would gladly do without looting tons of trash that only contributes to make inventory management a pain and take just the occasional reward that sells for a lot more money, by the way.
